Seat pad

Abstract

The present invention is a seat pad (1) including a backrest (12) that stands up from a rear side of a seat (11) on which an occupant sits and supports the occupant from behind, in which the hardness of a lower part (13) of the backrest (12) in a front-rear direction X that supports at least the waist of the occupant is lower than the hardness of an upper part (14) thereof in the front-rear direction X that supports at least the shoulders of the occupant.

1 . A seat pad, comprising:
 a backrest that stands up from a rear side of a seat on which an occupant sits and supports the occupant from behind,   wherein the hardness of a lower part of the backrest in a front-rear direction that supports at least the waist of the occupant is lower than the hardness of an upper part of the backrest in the front-rear direction that supports at least the shoulders of the occupant.   
     
     
         2 . The seat pad according to  claim 1 , wherein the upper part and the lower part are connected in a vertical direction, and a boundary between the upper part and the lower part is positioned in a central region when the backrest is divided into three equal regions including an upper region, a lower region, and the central region positioned between the upper and lower regions. 
     
     
         3 . The seat pad according to  claim 2 , comprising:
 a pair of side auxiliary parts that projects forward from both sides of the backrest in a left-right direction,   wherein the side auxiliary parts are provided integrally at least with the lower region and the central region of both sides of the backrest in the left-right direction,   wherein front edges of the side auxiliary parts are formed in a curved shape gradually projecting forward as the front edges go an inner side from an outer side in the vertical direction, and   wherein the boundary is positioned above top parts positioned furthest forward on the front edges of the side auxiliary parts and below upper edges of the side auxiliary parts.   
     
     
         4 . The seat pad according to  claim 1 , wherein a ratio of a size of many foam cells included in the backrest in a direction along a seating surface of the backrest to a size of the foam cells in the front-rear direction becomes higher when the foam cells are positioned closer to the seating surface side in the front-rear direction. 
     
     
         5 . The seat pad according to  claim 1 , wherein the hardness of the upper part in the front-rear direction is 1.5 times or more the hardness of the lower part in the front-rear direction. 
     
     
         6 . The seat pad according to  claim 1 , wherein the hardness of the upper part in the front-rear direction is 0.4 kPa or higher and 0.9 kPa or lower, and the hardness of the lower part in the front-rear direction is 0.2 kPa or higher and 0.4 kPa or lower. 
     
     
         7 . The seat pad according to  claim 2 , wherein a ratio of a size of many foam cells included in the backrest in a direction along a seating surface of the backrest to a size of the foam cells in the front-rear direction becomes higher when the foam cells are positioned closer to the seating surface side in the front-rear direction. 
     
     
         8 . The seat pad according to  claim 3 , wherein a ratio of a size of many foam cells included in the backrest in a direction along a seating surface of the backrest to a size of the foam cells in the front-rear direction becomes higher when the foam cells are positioned closer to the seating surface side in the front-rear direction. 
     
     
         9 . The seat pad according to  claim 2 , wherein the hardness of the upper part in the front-rear direction is 1.5 times or more the hardness of the lower part in the front-rear direction. 
     
     
         10 . The seat pad according to  claim 3 , wherein the hardness of the upper part in the front-rear direction is 1.5 times or more the hardness of the lower part in the front-rear direction. 
     
     
         11 . The seat pad according to  claim 4 , wherein the hardness of the upper part in the front-rear direction is 1.5 times or more the hardness of the lower part in the front-rear direction. 
     
     
         12 . The seat pad according to  claim 7 , wherein the hardness of the upper part in the front-rear direction is 1.5 times or more the hardness of the lower part in the front-rear direction. 
     
     
         13 . The seat pad according to  claim 8 , wherein the hardness of the upper part in the front-rear direction is 1.5 times or more the hardness of the lower part in the front-rear direction. 
     
     
         14 . The seat pad according to  claim 2 , wherein the hardness of the upper part in the front-rear direction is 0.4 kPa or higher and 0.9 kPa or lower, and the hardness of the lower part in the front-rear direction is 0.2 kPa or higher and 0.4 kPa or lower. 
     
     
         15 . The seat pad according to  claim 3 , wherein the hardness of the upper part in the front-rear direction is 0.4 kPa or higher and 0.9 kPa or lower, and the hardness of the lower part in the front-rear direction is 0.2 kPa or higher and 0.4 kPa or lower. 
     
     
         16 . The seat pad according to  claim 4 , wherein the hardness of the upper part in the front-rear direction is 0.4 kPa or higher and 0.9 kPa or lower, and the hardness of the lower part in the front-rear direction is 0.2 kPa or higher and 0.4 kPa or lower. 
     
     
         17 . The seat pad according to  claim 5 , wherein the hardness of the upper part in the front-rear direction is 0.4 kPa or higher and 0.9 kPa or lower, and the hardness of the lower part in the front-rear direction is 0.2 kPa or higher and 0.4 kPa or lower. 
     
     
         18 . The seat pad according to  claim 7 , wherein the hardness of the upper part in the front-rear direction is 0.4 kPa or higher and 0.9 kPa or lower, and the hardness of the lower part in the front-rear direction is 0.2 kPa or higher and 0.4 kPa or lower. 
     
     
         19 . The seat pad according to  claim 8 , wherein the hardness of the upper part in the front-rear direction is 0.4 kPa or higher and 0.9 kPa or lower, and the hardness of the lower part in the front-rear direction is 0.2 kPa or higher and 0.4 kPa or lower. 
     
     
         20 . The seat pad according to  claim 9 , wherein the hardness of the upper part in the front-rear direction is 0.4 kPa or higher and 0.9 kPa or lower, and the hardness of the lower part in the front-rear direction is 0.2 kPa or higher and 0.4 kPa or lower.